The invention concerns an electromedical implant as set forth in the classifying portion of claim 1.
Known electromedical implants, for example cardiac pacemakers, defibrillators, cardioverters or other electronically actuated or controlled implants generally have a close-range telemetry device for the exchange of data with an external apparatus. Close-range telemetry is usually employed in relation to after-care examinations of a patient in a clinic or a medical practice. In this case the external apparatus is applied for data transmission to the body of the patient in the proximity of the implant.
The close-range telemetry device usually includes a close-range antenna and a close-range transmitter/receiver unit with a close-range transmitter, a telemetry unit connected thereto and an antenna interface device which is connected to the telemetry unit and by way of which the close-range antenna is connected to the close-range transmitter/receiver unit.
Other known electromedical implants have a long-range telemetry device for data exchange with an external apparatus. In this case, instead of the close-range transmitter/receiver unit, they use a long-range transmitter/receiver unit which operates in the high-frequency range and which enjoys a greater range than the close-range transmitter/receiver unit. That means that there is no need for the external apparatus to be fitted to the body of the patient. It only has to be within the range of the long-range transmitter/receiver unit of the implant.
Close-range telemetry involves the disadvantage that interrogation of the implant is possible only in the immediate proximity of a programmer or a monitoring station, whereby the mobility of the patient is under some circumstances severely limited. In comparison, long-range telemetry entails the disadvantage that, although patient mobility is increased, a relatively large amount of energy is consumed, which is disadvantageous having regard to the limited energy supplies of such an implant.
In order to minimize the disadvantages involved, it would therefore be desirable to provide an implant with both telemetry variants. In this case however the problem which arises is that naturally only a relatively limited amount of structural space is available for such implants so that it is not readily possible for both telemetry devices to be integrated in the same implant.
Therefore the object of the present invention is to provide an electromedical implant of the kind set forth in the opening part of this specification, which permits simple integration of long-range and close-range telemetry.
Based on an electromedical implant as set forth in the classifying portion of claim 1, that object is attained by the features recited in the characterizing portion of claim 1.
The invention includes the technical teaching that integration of long-range telemetry in a fashion which does not give rise to problems and which does not involve a great deal of complication and expense in an implant of the general kind set forth, with close-range telemetry, is achieved if the circuitry expenditure for long-range telemetry is minimized by virtue of using the existing circuits for close-range telemetry. For that purpose it is proposed that, to provide a long-range telemetry device, there is additionally provided a long-range transmitter connected to the telemetry unit, while the other components of the close-range telemetry device are also used for long-range telemetry. That advantageously saves not only on structural space but also manufacturing cost.
Preferably, there is provided at least one long-range antenna which is connected to the antenna interface device, as the required antennae can be of a particularly simple structure while involving the need for a small amount of space and enjoying properties which are optimized in relation to the respective kind of telemetry involved.
Close-range and long-range antennae can remain connected in parallel with each other in operation as generally the two telemetry procedures are not in any case implemented simultaneously. It is preferably provided however that, for switching over between close-range and long-range telemetry, the close-range antenna and the long-range antenna are respectively connected to the antenna interface device by way of a switching unit.
The two telemetry procedures can be operated with the same modulation method. In preferred variants however it is also possible to apply different modulation methods, in which case there is provided a matching logic circuit which is connected to the telemetry unit, for adaptation of the modulation method for the respective telemetry involved.
In preferred embodiments of the implant according to the invention the long-range telemetry device is designed for operation at substantially the same effective data rate as the close-range telemetry device, thereby avoiding additional intermediate storage means.
In order to achieve adaptation in the simplest possible manner to the different demands of the two telemetry methods, a separate energy supply is preferably respectively provided for each of the long-range telemetry device and the close-range telemetry device.